This project is a study of the solution chemistry and liquid-solid equilibria of the two major components of urinary stones, calcium oxalate and uric acid. The studies will utilize perturbation of solubility as the primary experimental technique. Stability constants and solubility constants which will be derived from the studies will be applied to evaluation and management of patients with urolithiasis, and will also be used in experimental studies of the disease urolithiasis. Results obtained from this project will also have direct bearing and application on the physical-chemical aspects of the disease gout. This project is also an integral part of a long-term program of study on urolithiasis.